According to French Larousse Great Encyclopedia (chapter Ghana), the Union des Etats africains was born in 1961 when Ghana chose to get closer with marxist Guinea and Mali. It is said that the Union was very short. I first thought it lasted until Nkrumah lost power in Ghana (February 1966: there was a coup while he was in Guinea, where Sekou Toure had named him “co-president”). But French Quid Encyclopedia says (chapter Guinea) that the project of Union Guinea/Ghana was born in November 1958, and that a project of Union Guinea/Ghana/Mali existed in December 1960. Well, if it was “very short”, I’d say the project was stopped in 1962, when Guinea decided to have (temporarly) more relationships with the United States and less with USSR. What is sure is that the flag has never had more than 3 stars!